The electroluminescent element comprises a pair of counter electrodes and an organic luminescent layer located of electrons injected into the luminescent layer by one of the electrodes, with holes injected into the luminescent layer by the other electrode, occurs within the luminescent layer whereby between the the electrodes; recombination the luminescent substance is excited to a higher energy level. Energy in the form of light is produced when the excited luminescent substance returns to the ground state, which is luminescence.
Since the thin film organic compound is used as a luminescent layer, the carrier injection type electroluminescence element has come to provide high intensity luminescence.
The U.S. Pat. No. 3,530,325 discloses the use of single crystal anthracene as luminescent substance, and Japanese Patent LOP No. 59-194393 shows a combination of the hole injection layer and organic layer of the luminescent substance as a luminescent substance, while a combination of hole injection and carrier layer and organic electron injection and carrier layer is disclosed in the Japanese Patent LOP No. 63-295695, and a combination of the hole traveling layer, luminescent layer and electron traveling layer is exhibited in JP. Journal of Applied Physics, VOL. 27, NO. 2, P.269-271.
The intensity of luminescence has been improved in the conventional electroluminescent element having the said configuration, but the intensity of luminescence and durability is yet to be improved. A greater intensity of luminescence and a high degree of durability are desired.